Mothra vs. Godzilla marks the first crossover between two of Toho's own monsters: their flagship character Godzilla and the giant moth deity Mothra, introduced three years prior in her own film. When Mothra's egg washes ashore in Japan following a typhoon, greedy businessmen Kumayama and Jiro Torahata claim it as their own property and plan to exploit it for revenue. To make matters worse, Godzilla reemerges and begins rampaging across Japan, making his way straight for the egg. It's up to Ichiro Sakai, Junko Nakanishi, and Shunsuke Miura to travel to Infant Island and plead with the dying Mothra to return to Japan and battle Godzilla to save both her offspring and the millions of innocent people threatened by Godzilla's rampage.
This is a transcript of the Japanese opening credits of Mothra vs. Godzilla, as translated into English on the 2006 Classic Media DVD release of the film, and the opening credits of the American version of the film, Godzilla vs. The Thing.